Oiling system for rotary pumps



Mmh 9, 1943. H, A @ARTHUR mL l 2,313,387

OILING SYSTEM FOR ROTARY` PUMPS Filed Jan. 29. 1941 Patented Mar. 9,1943 STTES OILING SYSTEM FOR ROTARY PUMPS Herbert A. McArthur,Mundelein, and `lohn. B. Decker, Evanston, lill.

Application January 29, 1941,y Serial No. 376,484

l Claim.

This invention is directed to means for the conserving of oil employedin the lubrication of a rotary pump and circulating the same in such away as to constantly maintain a lm of oil between the moving surfaces.

In certain pump constructions with which we are familiar, and which areemployed for the purpose of maintaining vacuum conditions, difculty isexperienced by reason of the fact Vthat the lubricating oil follows theair currents through the pump and is dissipated and wasted in thedischarge of the air, which not only requires frequent replenishing ofthe lubricating supply but also tends to produce disagreeable odors andto befoul objects in the neighborhood of the air exhaust.

The present invention is intended to overcome these dimculties byproviding a return line for the oil in communication with the currentflow of the air, so that the oil, instead of being blown out in the formof a mist or vapor with the air,` will be sucked back into the systemand recirculated.

Further objects and details will appear from the description of theinvention in conjunction with the accompanying drawing, whichillustrates a rotary pump section, with the oil circulation system ofthe present invention applied thereto.

The pump to which the oil system is applied is of conventional form,comprising a casing I within which is located a drum-shaped chamber IIwhich houses a rotor I2 of less diameter than the chamber II, and whichis actuated by an eccentric I3 carried by a shaft It. The eccentricoperates within a ball race I5, so that 'as the shaft is rotated theline of contact of the rotor will progressively follow around the innercylindrical wall of the casing, thus progressively driving ahead the airfrom the point of inilow to the point of discharge, in a manner wellunderstood in the operation of rotor pumps.

As shown, the air is admitted through a pipe I5 into an air inletchamber II which communicates with the interior of the casing through aport I8 on the inlet side of a fin I9 slidably mounted within a bearingblock 2B carried by a depending partition ZI.

The 1in projects upwardly from the periphery of the rotor and serves toseparate the inlet port I8 from a corresponding outlet port 22, the wallof the chamber II being divided to aiord a gap through which the nprojects. The outlet port 22 communicates with a discharge chamber 23 incommunication with a threaded nipple 24 carrying a T-shaped coupling 25which unites witha depending lelbow 26. V l

The coupling is provided with an upstanding threaded leg 2l into whichAis screwed the end of a tube 23 provided with apertures 29 openingwithin a drum-shaped muliier casing 3E] which is closed by a peripheralcap plate 3| through which the air is finally discharged.

Save for the elbow 26; the pumpmechanism heretofore described is ofstandard or conventional formation and serves merely to illustrate arotor pump of the general character to which the oiling system of thepresent invention is applied, so that it will be understood that thedetails of the pump construction may be Varied or modified in numerousparticulars without departing from the spirit of the invention.

The oiling system includes a duct 32 which, as shown for purposes ofillustration, may be in the form of a separate pipe or tube, althoughthe duct might be afforded by a passageway drilled or cored through thecasing of the pump.

One end of the duct terminates within the inlet chamber I'I, and theduct extends therefrom through the outlet chamber 23, and through thenipple 24, the coupling 25, and the elbow 2B, and terminates in adownwardly extending leg 33 which enters a cup 34 secured by means of aclip 35 to a fitting 35 screwed onto the end of the downturned elbow 23.

The cup is held in place by means of a thumb. screw 3l which bearsagainst the base of the cup and holds the rim of the cup against awasher 38, so that the escape of oil is impossible.

Operation In operation, with the shaft ifi rotating in acounter-clockwise direction, the rotor will likewise follow the wall ofthe surrounding chamber in a counter-clockwise direction, so that airWill be drawn in through the pipe i6, chamber Il, and duct I3, and willbe forced around the periphery of the rotor and out through the duct 22,discharge chamber 23, and thence through the pipe lea-ding to themuiiier through which the airwill be discharged.

During the rotation of the rotor, there is a tendency for thelubricating oil to follow the air current and be forced out of the rotorchamber, but the oil being heavier than the air, and subject to asuction created through the duct 32, will pass downwardly through theelbow 26 and thence upwardly int-o and through the duct and back to theair inlet chamber Il for recirculation through the rotor chamber. Bythus providing a separate return passage for the oil, whose intake islocated at a level below the point of discharge for the air, the oilwill separate from the air current and be returned into the system,thereby avoiding the waste of oil and the disagreeable odors occasionedby the discharge of an oil mist into the atmosphere surrounding thepump.

The invention is one which may be applied to numerous forms of rotorpumps of conventional type without modifying the structure of the pumpitself, since it suices merely t provide a duct or passageway lea-dingback to the air inlet side of the pump, so that suii'icient suction willbe created to draw back the oil and prevent its escape with thedischarge of air.

Although the inner terminus of the oil duct is shown as leading directlyinto the air inlet chamber, it will suce to lead the duct into anyportion of the pump structure which is subject to the suction occasionedby the rotation of the rotor, and it is not the intention, therefore, tolimit the arrangement of the oil duct in the precise manner shown forpurposes of illustration. In fact, the oil duct might be led back intothe interior of the partition wall 2l above the bearing block 2D, whichis a region in some degree subjected to suction, so that, wheresoeverthe oil duct may terminate, a suiiicient suction will be created throughthe oil duct to prevent the escape of oil and return it to the interiorof the pump.

aslass? Although in the claim we have referred to the education anddischarge of air, it will be understood that the term air is intended toinclude any gaseous uid adapted to be dealt with by the pump of thepresent invention.

We claim:

In an oiling system for rotary pumps, the combination of a casingproviding a rotor chamber and a rotor eccentrically mounted forprogressive contact with the surrounding wall of the chamber to eductair therethrough, the rotor chamber being in communication with airinlet and air outlet chambers, the air outlet chamber having enteredthereinto the inner end of an externally extending tubular passageprovided with a port for the escape of air and being extended beyondsaid port and downturned to aford a passage for the separation bygravity of oil educted with the air from the rotor chamber, a cup belowthe end of the downturned passage, and a return oil duct having its endhoused within the cup and extending backwardly therefrom through thetubular passage and through the casing to the air inlet side of therotor .casing and terminating at a point subjected to the suctionoccasioned by the current of air entering the rotor chamber.

HERBERT A'. MCARTHUR. JOHN B. DECKER.

